If I Could Prove A Theory
by LxIsxJustice
Summary: "I think you'll find that I do, Bruce. I can make a pretty long list of things that will prove that theory, too." A Stark Party, gambling Avengers, a heartsick doctor and a genius-billionaire-playboy-philanthropist in action. Tony/Bruce Rated for lovin'.


** FUUUUUUUUUU—Avengers was amazing! I have now seen it a total of six times, along with a re-watch of all the previous hero movies. Watching all those movies again…-insert expletive of choice- It was re-living my childhood! When I was little I had (and still do) fourteen binders of comics, consisting of hundreds upon hundreds of illustrated goodness. I played with figures of heroes instead of Barbies and cuddled with my squishy Hulk plushie when I fell asleep. So The Avengers in 3-D on opening night? Yeah, basically made me nerd-gasm hardcore. And I think my ovaries exploded at the sheer sexiness throughout that entire film. Before you read, let's get one thing straight. Mark Ruffalo (Bruce Banner) is mine. M-I-N-E. And in the words of Tony Stark: "Don't take my stuff." ;) So I will loan you his absolutely geeky hotness for this fanfiction, but if you take him away, shit will get serious. Clear? Good. Anyways, this fic is dedicated to a dearie over on Tumblr, ****onmyowninaseparatesky, ****who's Avenger love (And Supernatural and Sherlock Holmes and Doctor Who and Lord of the Rings love) rivals mine. She also posts the most hilarious and sweet memes. Thank you, lovely, for making my time in the hospital go by super-fast. It is a Tony/Bruce fic, with humor and romance and the slightest bit of angst/hurt/comfort. If you want the full effect, listen to "Scream" by Usher while reading and read Bruce's backstory online. It's not happy, but it sure describes why he hates alcohol. The tense changes partway through; it's on purpose. I wanted to show Bruce living in the past versus living in the present. I'm pretty much on a Dr. Banner rampage (no pun intended) right now, so he's going to inevitably get paired with…pretty much everybody. Sorry Mark, you're just too sexy for your own good.**

**Disclaimer: I own only the ungodly amounts of comics hidden under my bed so that no one realizes just how alone I am going to end up, and my Hulk Plushie, who turned seventeen this year. In a very Hulk fashion, he is almost completely undamaged. Me owning Mark is pretty much just fantasy…but I can dream, right? Enjoy!**

The bass thudded in steady rhythm that contrasted perfectly with Dr. Banner's heart.

_This was a really, _really_ bad idea. _He mused to himself, feeling his body jostled and bumped into by the masses of people that were all somehow packed into the room…and the rest of Stark Towers.

The sheer overstimulation his body and senses were currently undergoing was, to put it bluntly, freaking him out. He hadn't been near this many people in years (India didn't count, because at least there were always nooks to slip into) and the sudden re-introduction into society made him dizzy. He knew it had nothing to do with the alcohol that flowed freely—he had a feeling there was no such thing as a Stark party _without_ liquor—because he hadn't imbibed any. Alcohol was _not _okay with him.

The heat was high, that many bodies packed into a small area had that ability, and all the movement and talking and running into him had him on overdrive. The music was loud, a male voice rapping and singing lyrics that had Bruce blushing.

He apologized for what was legitimately the hundredth time as someone knocked into him, trying to find somewhere, _anywhere_ to escape so he could calm down for a bit. There was really no risk at the moment of him Hulking Out, he was just really nervous and over-tired thanks to the vast amount of S.H.I.E.L.D agents that were roaming the place, but Bruce Banner had quickly learned a simple equation long ago. Bruce plus large amounts of people equals _bad_. Add alcohol and a lack of sleep to the mix, and there was the most perfected recipe for disaster. He supposed if it got beyond his control, he could go to the Green Room that Tony had so kindly provided him with, but people might notice loud crashes and thuds. Especially Agent people.

Speaking of Tony, he should probably let his friend know he was turning in for the night so the metal avenger wouldn't stay up looking for him. _Friend…_he shook the beginnings of dangerous thoughts that could _wait_ until he got to his room. He scanned the room he was currently in, looking for the familiar face, but didn't see him. Sighing, he began to search. _Why does one man who lives alone—or close to it—have this many rooms? _Everyroom held about two hundred more individuals, but not the one he was seeking.

As he craned his neck to look into another room, he felt a hand on his shoulder. He barely contained the flinch, but smiled when he saw Pepper standing behind him with a grin. "Hey, Bruce! Looking for someone?" she asked happily. Social events were all her, and she was good at them. Bruce smiled lopsidedly, nodding. He glanced around nervously, trying not to show his jitters in front of her.

"Yeah, I was looking for Tony. Just wanted to tell him I'm not sticking around for the rest of the event. No offense to you, Ms. Potts, you sure know how to throw a party, but I just think it would be safer for the guests if I weren't here," he replied, rubbing the back of his head, embarrassed. He knew Pepper accepted him in the house, and even trusted him to an extent, but it still bothered him that he had to bring it up.

She laughed, quirking a brow. He sometimes wondered if Tony had taught her that, or if it was the other way around. Even if they weren't dating anymore, they still lived together and had influenced each other in the past. He'd put his money on Pepper. "Aw, I don't know. We could just say it was a cool party trick. I know Tony would get a kick out of it." It was said sarcastically, but Bruce smiled, chuckling.

"I know he would. And we certainly can't have Tony getting more spoiled than he already is," he said indulgently. Honestly, there wasn't much he wouldn't do for Tony Stark. But that was beside the point.

She rolled her eyes. "God forbid. Anyways, I think I saw Tony earlier in the side lounge. Seems like there's some sort of rave going on in there. I don't think you should venture into _that _lair. Assuming of course that keeping clothes _on_ was the purpose of not Hulking Out." His face fell slightly, trying desperately not to think of the activities Tony may or may not be engaging in—"Being single is _awesome_, man!" he'd said—and Pepper noticed. "Get some sleep, Bruce. Tony…well…" He knew what she was trying to say. She was a genius in her own right. She could see right through him.

"Yeah, I know. Goodnight, Pepper," he mumbled as he turned to walk away.

"Hey, you're making progress! You called me Pepper," she quipped lightly, staying just long enough to see his brief smile before disappearing into the throng of people.

He tried to make his way to his room quickly, but he was stopped by the other Avengers before he even got close. "Bruce, Son of Banner! Where are you fleeing to so quickly?" boomed Thor's voice and he cringed, hoping this conversation would be quick. "And why do you not have a glass of this lovely nectar?" he asked, holding up a glass of alcohol.

Steve made a face and muttered that it was "better in the forties", but Natasha cut him off. "Have you seen Tony, Bruce? He owes me twenty dollars." Steve grumbled again, blushing and running a hand through his blond hair.

"Why?"

The spy looked him up and down in a way that felt appraising, and he ducked his head under her scrutiny, fiddling with his busted watch. "No reason. Just a bet we had going. I found proof that I won. I'd like my money now."

Bruce felt his brows furrow. "Why now?"

"I have a feeling I'm going to owe Clint twenty dollars by the time the party's over. Just another bet," she waved off his question with an airy gesture of her hand, glancing briefly at the archer, who had simply stood smirking the whole time. "So, have you seen him?"

He shook his head. "No, I was looking, but couldn't find him. Pepper said he was in the side lounge, but I didn't feel up for braving rave lights. Have fun." He sighed, nodding to each of them before turning back in the direction of his room.

He didn't catch the look of knowing the others shared.

When he got to his room, he immediately closed the door and slumped against it. _So tired…_

When he turned around, he kicked off his shoes, not bothering to turn on the lights, since he would just have to turn them off in a few minutes anyways. He could do without the thudding music blaring loudly all the way from the living room, but he was just exhausted enough to let it become background noise. He stripped off his shirt and tossed it to the end of the bed, before deciding he was too tired to bother stripping completely and slid into the bed. Giving a silent thanks to Tony, as he did every night, for giving him a place to stay, he pulled the covers over him and tried not to think about that he was sleeping alone once more. He let a few thoughts about his and Tony's car project drift through his head, making a few adjustments to the schedule to accommodate Tony's inevitable headache he would no doubt have tomorrow. Satisfied, he settled in to fall asleep.

Except, twenty minutes later, he was still awake. He growled at his overactive mind that kept wondering _Where is Tony now? Did the others find him? Is he okay? Is he having a good time?_ These questions and more swirled in his mind, each centered around the genius, billionaire, playboy, philanthropist friend of his. He snorted indignantly. Tony didn't give himself enough credit with just those four words. The others would say his ego was stoked _more_ than enough on just those, but Bruce knew better. Tony was as wounded as the rest of them. He had as many insecurities as himself, and if it wouldn't be interpreted the wrong way—or in his case, the correct way—he would tell Tony everyday how amazing he was. Just the fact that Tony had not only given him a home and protection from S.H.I.E.L.D, but had opened up at about his past spoke to their friendship, but he also knew it spoke of nothing more.

He groaned at the direction his thoughts had taken him, clenching his fists near his pillow and resisting the urge to succumb; to set himself down the path of release. _Don't do this to yourself, Banner._ He told himself firmly.

Instead, he let lists of descriptors float through his mind, some of which he made up on the spot, because Tony deserved his own adjectives. He'd just gotten to the "D" list, the last one being 'debonair', when suddenly the door swung open with a definitive bang. Bruce scrambled into awareness, nearly leaping out of bed to face down whoever was in his room. He had mere seconds to register an eerie blue glow at the center of the figure in his doorway before it launched itself at him.

"Holy sh—" he didn't get to finish the expletive when the breath was knocked out of him, and he found himself on the bed, pinned by one Tony Stark. Or that would explain the glow. "Wha—?" he started to demand what the hell was going on before warm lips were pressed to his neck, and he let out a squeak_. _A_ squeak_. At least it wasn't the Other Guy's roar. "Tony?" he wheezed out, trying to push him off so he could ascertain whether it really was his friend. "What are you…?" he was rendered speechless once more.

Tony sat back at his pushing, the glow of the arc reactor lighting his face and bringing shadows across the room. He was staring at Bruce with eyes that _burned_. It wasn't just a smolder or a teasing glint like he reserved for women and his friends. This was…this was nothing he had ever _seen_, much less on Tony. And it was directed at him. _Oh god…_

"Tony, what's going on?" he asked, cursing the breathy, shaken voice that he asked in. "Are you alright?"

The taller man smiled slightly at his question and answered quietly, "No, I'm not alright. I haven't been for months." Bruce felt his heart stop. Was Tony—no, it was too horrifying to think.

"Is it…the reactor again?" he whispered, remembering how Tony said the last model had almost killed him. _Please, please, don't take him away…_He pleaded, before being startled by laughter. It was quiet at first, before escalating into the warm, deep timbres Bruce was already so used to.

"Bruce! You sure you have eight P.H.D's, man? 'Cause right now you're missing the entire _equation_, much less the variables," he laughed, before the chuckles faded and the_ burning_ was back. "What I meant was; I've been fucking miserable. And it's your fault." His smirking face came just a little closer, and Bruce could feel his heart speed up with the proximity. He thought he knew what Tony was saying, but there was _just no way_. But, he also couldn't remember a moment recently when Tony seemed down about anything. "You see, it's occurred to me that I have the smartest, nerdiest, hottest scientist this side of the universe living _in my house_, and I haven't done anything about it. That's such shitty logic that I'm pretty sure even Thor was awed by the sheer stupidity of it all." Bruce had no idea, no _clue_, how he had suddenly ended up on his back once more, with Tony braced over him, but _ohgod _this was not what he had been expecting this evening and he was never one for big surprises. This though…perhaps he could live with.

His mind was at war, trying to resist the overwhelming desire to draw Tony closer, the overwhelming desire to push him away, and the most urgent need to pass out so his mind wouldn't snap from the thought that Tony Stark was currently lowering his head to brush his lips along Bruce's jaw.

"I plan to solve that problem _immediately_." He whispered such promises. But Bruce was nothing if not in control of himself, and he still didn't know _what was going on_. He quickly pushed Tony back, trying to determine whether his friend was intoxicated.

"Are you drunk?" he asked, somewhat coldly, because if he was…Bruce was leaving on the first plane out of New York. He couldn't do this to Tony or himself if it was just some joke or inebriated tumble. Alcohol…humanity had never come up with a better poison. Luckily, Tony had the audacity to look hurt, bringing him back from memories that would end up with him tearing the building apart.

"No. I'm not drunk. I only had two glasses of the most god-awful fruity drinks—in case you haven't noticed, I like Scotch, not stupid margaritas—to make sure of that. You've seen me drunk; you've _all_ seen me drunk. This is not it. And speaking of everyone else, Natasha and Barton are going to be unbearable for the next couple weeks. And Steve will probably look at you like you've grown a second head, or at least Loki's reindeer antlers. They may or may not have won some bets involving us, but hey, on the plus side, since they already know, it won't be a problem for us to—"

"Tony, you're rambling." Bruce raised a critical brow, remembering Natasha's comments about bets, Clint's smirking face, and Steve's embarrassed blush. It was starting to add up.

"Right. So anyways, that's why I'm in here. Because I will not have it said that Tony Stark doesn't chase what he wants. And you, Bruce…" he leaned in again, thoroughly stunning the shorter man once more, and breathed, "Are most definitely what I want." His hand moved towards the front of Bruce's pants, fiddling with the zipper and making the scientist's mouth go dry.

"B-but, you don't—" Bruce was cut off, stopped by the softest lips he had ever encountered. Not that he'd experienced many…or hardly any, but that was beside the point. His eyes fluttered shut and his arms wound around Tony's shoulders, bringing him closer while his mind screamed to _protect yourself, you idiot! You hurt the ones you love! Don't!"_ He pulled away for a moment, watching Tony's eyes open slowly with that burning, and he didn't care about reason for a moment. Their lips met again, this time less gentle and more passionate as Tony leaned over him once more.

"I think you'll find that I _do_, Bruce. I can make a pretty long list of things that will prove that theory. I joined the Avenger's team not planning on staying. I honestly just wanted to meet the brilliant Dr. Banner. When you turned out to be the best science-bro a guy could ask for, I stayed. Therefore, you are more important than my pride." He finished the sentence with a kiss to Bruce's eyelids, before continuing, "I built the Green Room, which drained one of my banks in Australia, and gave you an entire lab with all the fun toys, which wiped out two others. Therefore, you are more important than my money." He then kisses his cheek. "I broke up with Pepper because I had so many feelings channeling your way that there wasn't much left for her. I also haven't touched anyone since. Therefore, you are more important than my sex-life (which I will have you know, was _a lot_ to give up for almost four goddamn months)." This time it's his neck, and Bruce is losing his mind. But Tony isn't finished. "I also happen to find your geekiness to be the most adorable thing ever, your quiet nature to be the perfect balance to my, well, _I_ call it awesomeness, but I think Natasha would call it a whole lot of other more colorful names. You're sexy as hell, though I know you'll never admit it, and you…make me forget myself." Tony looked back up at Bruce, who is having more trouble breathing than he would if he was Hulking Out, and smiled so brilliantly, Bruce wondered if he's ever really seen Tony smile.

"The others have been annoying the hell outta me with their 'Hulk has a really skinny shadow' jokes. And when I say you make me forget myself, I mean literally. I sometimes forget I exist, because everything is suddenly about _you_, not me. Frankly…I'm starting to like it that way," he finished, raising a hand to brush it through Bruce's errant curls. The cheeky grin is back. "So, that enough proof for you, Doc? Can we proceed in the evening's agenda?"

Before he can even question whether or not this is a good idea, Bruce's mind has already made a decision. He draws Tony down for a fierce kiss, their lips crushing one another's and dueling in 'glorious battle' as Thor would say. Their tongues twine and suddenly it isn't battling anymore, but fighting _for_ each other. "I'll take that as a 'yes'." Tony threads his fingers through Bruce's hair and Bruce clutches at Tony's shoulders to keep him grounded. There is a reason he's been celibate for most of his life, but somehow, he doesn't feel afraid of losing control this time. Maybe it's because he's got a much better handle of the Other Guy than he used to, or maybe it's because they haven't gotten to anything _too_ amorous yet. Honestly, he thinks it's because of Tony. The man blows through every scientific law he's ever come across, so why should he not be different in this way too? He _would_ be the one to keep the monster at bay, because he is the only one who doesn't fear him. "Me too. I…and you…" he blushes at his leaden tongue, trying to stammer out the words Tony more than deserves to hear.

"I know. Don't worry, it's mutual." That playful voice combined with those deadly serious words should _really_ and_ truly_ be illegal.

Clothes are torn off so rapidly, that Bruce suddenly panics, thinking he's just gone manic despite his earlier thoughts, but Tony just shushes him and laughs at his deer-in-headlights look. His noise of protest at the jeer is swallowed into Tony's mouth, and he finds he can relax once more. Nothing cataclysmic has happened.

Almost of their own accord, his hips undulate, seeking friction against the lithe strength of Tony's body. A sharp moan is wrenched from his throat when Tony complies and grinds his pelvis into him. _Ah, there's the cataclysm_. The pace begins almost frantically, feverish skin against feverish skin, like the beat of the music he can still hear blasting from distant speakers.

They rock against each other fervently, claiming each other's mouths over and over again, until Tony slides down a little to suck at his throat and leave small bruises that will probably make Bruce embarrassed later when the others see them. Bruce can feel Tony smile against his collarbone and he wonders if they just had the same thought. The scientist thinks he's going to die of overstimulation when Tony's tongue darts out to flick against a nipple. "Tony!" he gasps. Slim fingers dance and skitter across his tanned chest and down his abdomen to his thighs, moving his tongue along the path his hands have taken, before gripping his hips and moving back to stare _very _appreciatively at the erection Bruce knows is his next target. He slides a hand to Tony's shoulder to stop him, shaking his head and gasping out, "N-Not tonight. I'd rather…" he blushes, unable to even speak his desires for the evening through his embarrassment.

Tony just grins and crawls back up, understanding completely. He lays a gentle kiss against a mouth that has driven him insane for nearly four months before he suddenly jolts and moans when he feels a warm palm encircle his aching length in a grasp so intimately perfect that he has to shudder and drop his head against Bruce's chest. He can feel the rumble of laughter in the shorter male's chest, but he doesn't mind it. It's Bruce; he's not laughing _at _him. With him. It's a giddy feeling to have someone to laugh with.

The hand strokes him and he is so aroused that it's nearly to the point of pain. _Fuck, if this is what I miss during an idiotic self-imposed dry spell, then never again!_ They need to decide something very quickly if they have any plans of continuing. By the looks of it, Bruce is in the same state he is, and there will be plenty of time for slow and sweet later. Right now…

"Which—" he starts, only to be answered before he can get the question out.

"You. Just in case." Tony frowns briefly, muttering something that sounds suspiciously like 'you a damn mind-reader now?' before the grin that should _also_ be a felony or at least finable is back and Bruce's neck is assaulted once more. The noises coming from his throat are too embarrassing to name. But Tony seems to be enjoying them thoroughly, so he makes no move to stifle them. _Losing control _can_ be fun_, he muses idly before thinking becomes impossible.

He lets himself feel every sensation, every caress and breath and crook of slickened fingers within his body. When his vision goes white and he nearly screams, he knows Tony has found what he's looking for. He now has the power to make Bruce come undone. And Bruce is relishing in it.

The fingers slip out of him, and he can't help but feel a bit of loss, though he knows they will be replaced by something better. When Tony is fully sheathed within him, he lets go of the breath he didn't know he was holding. This…complete, full feeling is so foreign, and yet he knows it's everything he's been looking for. When they move, there is no hesitance; only abandon to the intensity that has been rising since Tony stepped into the room. If Bruce never has another moment like this, he will still die a happy man. But Tony is promising a thousand nights of this and more; safety, companionship, understanding, and love. He can't help the tears that escape his eyes at the magnitude of such a promise. Tony kisses each of them away. Bruce's body writhes and shudders with each thrust, his mind is swept blank by the adoration and care and pleasure Tony puts into each movement. He is _home_.

When the spring eventually coils too tight, they are thrown from the ledge and fall, shouting and howling each other's names, into the white-space of ecstasy. It is more blissful than any yoga Bruce has ever practiced. When he regains some semblance of air control, Bruce blearily opens his eyes to smile at Tony; who doesn't have as much practice at regulating his breathing and is staring back at him with all the love Bruce could possibly want.

He leans over to kiss Tony once more before shifting and drawing him into his arms. "You don't strike me as a cuddler, but bear with me for a few minutes," he sighs, closing his eyes and just letting this bliss wash through him. He cracks a sleepy eye open when Tony snorts.

"Well, I haven't been in the past, yeah. But, daily near-death experiences make you appreciate a little cuddling. We'll just say it was totally manly if anyone asks," he says, laughing, and Bruce smiles before draping his arm over Tony's hip and beginning to doze off.

They're both near sleep when Bruce gives a grin and a half-snort-half-chuckle and mumbles, "Well, hooray for near-death experiences."

_Finis_

**Read and Review! :3 Ohhh yup, there will be more of these two in the future, but only if you ask for it.**


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